Computer only turns on

[Rv5v]

 I was watching YouTube on my pc and then suddenly my keyboard,mouse,headset and monitors all stopped. They all have power and my monitors have lights indicating they're on but when I turn my pc off and on it only lights up my keyboard and nothing else. I tried doing some stuff from the virtual agent but nothing helped. 

[Rv5v]

Aldo I really need my computer to work as I have important documents that I need this week.

[Lil_Boy_Blue]

Hi
First:- Turn off the computer, press and hold the PWR button for 4 seconds.

Then - Leave only keyboard and mouse connected, disconnect all externally connected
devices such as Docking Station, USB storage devices, displays, and printers.
Unplug the AC adapter from the computer.

Next - Press and Hold the Power button for 15 seconds to Hard Reset.
Rinse and Repeat; Re-Connect the AC adapter.

NOW begin checking/testing/proving the Hardware is fit for purpose.
Power on your PC, press ESC (repeatedly), then F2 at the prompt.
Choose System Tests (Fast Test does a 4 minute hardware check).

If you can, but with a dead screen it may not work.  Therefore next might be...

[Rv5v]

Didn't work, the only thing that's lit up on my computer is the tower and my keyboard put nothing else, also how could I check the hardware without seeing the screen?

[Lil_Boy_Blue]

Hi

Because sometimes the HARD RESET can effect a repair.

Normally if a piece of hardware fails there are "beep codes (LED flashes)" to indicate the area of error.

You have none of those, therefore I suggest a second opinion, rather than me keep guessing.